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In a multi-controller software-defined networking (SDN) architecture, solving the controller placement problem (CPP) has a direct effect on the generated control overhead in the network. We aim to minimize the control overhead exchanged in the network, especially in software-defined multihop wireless networks (SDMWN), i.e., a network that is built on multihop communications using a wireless medium. We solve this problem both optimally, using a nonlinear optimization model, and via a heuristic algorithm. The proposed heuristic approach is based on the genetic algorithm (GA). The objective of both the proposed optimization problem and the proposed GA algorithm is to find a given number of controllers, controller placements and assignments of controllers to devices while minimizing the generated control overhead in the network. Our results show the impact of different metrics, including the number of controllers, the arrival rate of new flows and the capacity limit of wireless links on the control overhead and the average number of controller-device and inter-controller hops. In addition, our results demonstrate that the GA-based heuristic approach can derive the same optimal solution for a small network with much less computational overhead, and can solve larger networks in a short period of time, making it feasible for non-trivial network sizes. [ABSTRACT FROM AUTHOR]

Software-Defined Networking (SDN) has been largely used in wired networks to separate the control plane and the data plane and enable users to programmatically change the networking capabilities. This investigation focused on understanding how SDN concepts could be applied in a networked embedded systems environment where the nodes have limited capabilities and the wireless links have limited bandwidth. The goals were to realize the benefits of SDN while maintaining the network's topology and connectivity. A SDN controller was implemented on BeagleBone Black Board and interfaced with a networked embedded system via a SINK node. The approach was validated through simulations and experiments based on a physical testbed in multiple scenarios. In the future, the design can be extended to a fully capable Wireless-SDN system for use in a variety of applications such as Healthcare Systems, Internet of Things and Advanced Manufacturing Systems. [ABSTRACT FROM AUTHOR]